In the late 19th early 20th century, immigration was a ongoing issue in the United States. Congress started passing laws restricting the flow of immigration into the states. Two of these laws are the Emergency Quota Act of 1921 and the Immigration Act of 1924. These lawsThe Immigration Act made permanent the basic limitations on immigration into the United States established in 1921 and modified the National Origins Formula established then. In conjunction with the Immigration Act of 1917, it governed American immigration policy until the passage of the Immigration and Nationality Act of 1952, which revised it completely.
For the next three years, until June 30, 1927, the 1924 Act set the annual quota of any nationality at 2% of the number of foreign-born persons of such nationality resident in the United States in 1890. That revised formula reduced total immigration from 357,803 in 1923-24 to 164,667 in 1924-25. The law’s impact varied widely by country. Immigration from Great Britain and Ireland fell 19%, while immigration from Italy fell more than 90%.  The Act provided that beginning July 1, 1927, the formula would no longer use a percentage.
As of that date, total immigration would be limited to 150,000, with the proportion of the total admitted from any country based on that country’s representation in the U. S. population according to the 1920 Census. The change from 2% to 150,000 planned for 1927 was later postponed to July 1, 1929. The Act established preferences under the quota system for certain relatives of U. S. residents, including their unmarried children under 21, their parents, and spouses aged 21 and over. It also preferred immigrants aged 21 and over who were skilled in agriculture, as well as their wives and dependent children under age 16.
Non-quota status was accorded to: wives and unmarried children under 18 of U. S. citizens; natives of Western Hemisphere countries, with their families; non-immigrants; and certain others. Subsequent amendments eliminated certain elements of this law’s inherent discrimination against women. The 1924 Act also established the “consular control system” of immigration, which divided responsibility for immigration between the State Department and the Immigration and Naturalization Service.
It mandated that no alien should be allowed to enter the United States without a valid immigration visa issued by an American consular officer abroad. It provided that no alien ineligible to become a citizen could be admitted to the United States as an immigrant. This was aimed primarily at Japanese and Chinese aliens. It imposed fines on transportation companies who landed aliens in violation of U. S. immigration laws. It defined the term “immigrant” and designated all other alien entries into the United States as “non-immigrant”, that is, temporary visitors. It established classes of admission for such non-immigrants.